Hello ​@Gabbe18 and welcome to the Klaviyo Community!

There isn't a built-in feature to automatically resend confirmation emails to subscribers who haven't completed the double opt-in process. However, here are some strategies you might consider:

1. Implement a "Check Your Email" Page:

   • After a user submits the sign-up form, redirect them to a page instructing them to check their inbox (and spam folder) for the confirmation email.
   • Provide guidance on what to look for and emphasize the importance of completing the subscription process. For example, if you have an incentive, you can let them know they will miss out on it if they don’t confirm. 

2. Switch to Single Opt-In:

   • If appropriate for your audience and in compliance with your local regulations, consider using a single opt-in process to reduce friction.
   • Be aware that this may increase the risk of adding unengaged or invalid emails to your list, so monitor your list quality regularly.

I hope these suggestions are helpful. If you have any further questions or need additional assistance, feel free to ask!

Thanks for the tips!

I will try the check your email page because singe opt in is not feasible for me because it would dilute my audience too much with bots and invalid emails.

Btw, I also think Klaviyo should really add this feature to their product!

Klaviyo should definitely have an option to send a reminder automatically, this is basic Newsletter Marketing. 
We just switched to Klaviyo, and this is something I am really missing now!